Hydraulic regulator particularly for fuel injection pumps of internal combustion engines



May 20, 1969 Filed Dec. 27, 1967 HYDRAULIC REGULATOR PUMPS OF INT E.BESSIERE 3,444,849 PARTICULARLY FUEL INJECTION ERNAL COMBUST ENGINESSheet May 20, 1969 P. E. BESSIERE 3,444,849

HYDRAULIC REGULATOR PARTICULARLY FOR FUEL INJECTION PUMPS OF INTERNALCOMBUSTIONENGINES Filed Dec, 27, 1967 sheet 3 of 4 FOR FUEL INJECTIONION ENGINES Sheet 3 Wm m i a P. E. BESSIR REGULATOR PARTICULARLY MPS OFINTERNAL COMBUST a I @im May 20, 1969 HYDRAULIC REG P. E. SESS ULATORPARTIC OF INTERNAL MBUST PUMPS Filed DeC. 27, 1967 llll FOR FUELINJECTION ION ENGINES eet 4 of 4 United States Patent O Inf. cl. F02111/04, 1/06 U.S. Cl. 123-140 9 Claims ABSTRACT OF THE DISCLOSURE Anr.p,rn.dependent regulator for varying the fuel quantities delivered byfuel injection pumps, including a control element formed as a pistonthat reciprocates in a bore with a frequency depending upon the r.p.m.of an internal combustion engine associated with said fuel injectionpumps; an accumulator into which liquid is displaced by the controlelement during each pressure stroke, a spring-biased accumulator pistonwhich, during each suction stroke of the control element, Vforces theliquid out from the accumulator; conduit means which are opened andclosed by the control element in such a coordinated manner that duringeach suction stroke, provided the frequency of reciprocation of thecontrol element exceeds a predetermined rpm., the liquid displaced frornthe accumulator is allowed to expand into a cylinder displacing to avarying extent a regulating piston connected to the fuel quantitycontrol members of the fuel injection pump.

Background of the invention The invention relates to a hydraulicregulator particularly for fuel injection pumps of internal combustionengines. The regulator has a piston-operated accumulator including aspring which urges the accumulator piston against an abutment into itsposition of rest and wherein the force of the spring varies with itsexcursion. The accumulator is adapted, lirst to be hydraulicallyconnected with a liquid source under pressure, causing the accumulatorspring to be compressed so that its force increases and secondly, to behydraulically connected with a regulating device including aspring-biased regulating piston that is periodically exposed to thepressure prevailing in the accumulator.

It is known in the prior art to provide a fuel injection pump with ahydraulic regulator wherein the pump work chamber of the fuel injectionpump has a discharge channel which is opened by the accumulator pistonafter the pump has executed a predetermined portion of its stroke. Fuelinjection is thus terminated before the end of the delivery stroke. Sucha regulator, which may be used only with fuel injection pumps having asingle pump work chamber, is disclosed in U.S. patent to P. E. Bessire,No. 3,141,414.

Object and summary of the invention A principal object of the inventionis to provide an improved hydraulic regulator which is adapted to adjustthe quantity control member of a multi-cylinder pump, such as thequantity control rod of a serially connected pump.

Briefly stated, the aforenoted hydraulic connections are made and brokenby a control element in such a coordinated manner that the accumulator,after being cut olf from the liquid source and before being connected tothe regulator, is in communication with a r ICC chamber of lowerpressure for a duration which is a function of the r.p.rn. to beregulated. The conduit connecting the accumulator with said chamber oflower pressure includes a throttle passage to dampen the motion of theaccumulator piston.

According to a preferred embodiment of the invention, the controlelement, driven with a speed depending upon the r.p.m. to be regulated,is a piston which executes alternating pressure strokes and suctionstrokes. The bore in which the control element reciprocates defines apump work chamber which, during said pressure strokes performs thefunction of the aforenoted liquid source and during said suction strokesis transformed into the aforenoted chamber of lower pressure.

Brief description of the drawings FIGS 1-4 are axial sectional views ofan embodiment of the invention is different operational positions.

Structural description of the embodiment In a bore 1a of a housing Hthere is disposed a control element 1 which serves both as a pump pistonand as a control shuttle. The control element reciprocates to and frowith a frequency proportion to the r.p.m. of an internal combustionengine to which fuel is delivered by an injection pump associated withthe regulator according to the invention. While the pressure stroke orinward motion of the control element 1 is effected by means not shown,such as a cam, the return force for the suction stroke or return motionof element 1 is supplied by a spring 2. The outer cylindrical face ofthe control element 1 in the vicinity of the upper end thereof isprovided with a circumferential annular groove 3 which is connected witha pump work chamber 5 through a conduit 4 extending within the controlelement 1. Chamber 5 forms the upper terminal section of bore 1a.

The pump work chamber 5 is supplied with liquid through a conduit 6which is in continuous communication with a liquid supply tank,schematically indicated at 7. Communication is established betweenconduit 6 and chamber 5 through conduit 4 and groove 3 as the latterregisters with conduit 6 when the control element 1 is in, or adjacent,its lower dead center.

In a bore 8a of housing H there is slidably disposed an accumulatorpiston 8 which delimits an accumulator chamber 9. In bore 8a there isalso disposed a spring 22 which urges the accumulator piston 8 into aposition of rest against an abutment 21 fixedly held at the lower end ofbore 8a. In the position depicted in FIG. l, the tension of, or theforce exerted by, spring 22 is at a minimum value. The more theaccumulator piston 8 is displaced from its position of rest by means tobe described later, the more the spring 22 is compressed and thus thegreater its bias will be. Simultaneously with the increase of the biasof spring 22, the hydraulic pressure in accumulator chamber 9 alsoincreases as it will become apparent later.

The pump Work chamber 5 communicates with the accumulator chamber 9through a conduit 10 in which there is disposed a check valve 11permitting a liquid ow only from the pump work cha-mber 5 to theaccumulator chamber 9 while 'blocking any ow in the opposite direction.During each pressure stroke, the control element 1 displaces a`determined quantity `of liquid into the accumulator chamber 9 lso thatthe accumulator piston 8 is displaced from its position of rest into anew position where it opens a transfer port 23 which is connected to thelow-pressure liquid tank 7. This condition is shown in FIG. 2. Theposition of accumulator piston 8 represented by this figure thus placesan upper limit for the maximum possible ypretensioning of spring 22 andconsequently for the maximum possible hydraulic pressure in theaccumulator chamber 9.

From accumulator chamber 9 there extend two conduits 12 and 16, merginginto bore 1a at `different heights thereof. As the control element 1,subsequent to a pressure stroke, performs the initial or first part ofits return or suction stroke, at least part of the liquid, displacedinto accumulator chamber 9 during the preceding pressure stroke, willflow therefrom through conduit 12 and its throttle passage 13, thesectional area of which is adjustable `by means of a throttle needle13a.

Simultaneously with said liquid diow, the accumulator piston 8 moves inthe direction of its position of rest toward abutment 21 and is dampenedin its motion by virtue of the throttle passage 13. The duration .oflliquid ilow through conduit 12 is dependent upon the r.p.m. of theengine as it will become more apparent `as the specilication progresses.

During the second part of the suction stroke of control element 1,communication yis established through conduit 1-'6 between theaccumulator chamber 9 and a cylinder 15 in which there is slidablydisposed a regulating piston 18. This hydraulic interconnection of theaccumulator chamber 9 with the cylinder 15 occurs during the suctionstroke after the groove 3 shifts out of alignment with respect toconduit 12. The aforesaid connection between chamber 9 and cylinder 15is interrupted before, during a subsequent pressure stroke of thecontrol element 1, liquid is displaced from the pump work chamber 5 intothe accumulator chamber 9 The regulating piston 18 is biased by means ofa spring 19 which urges it into a position of rest against an abutment20 txedly held within the cylinder 15. The regulating piston 18 isconnected to a quantity regulating element, such as a regulating rod, ofthe fuel injection pump.

During the pressure stroke of the control element 1, the conduit 12 isopened by registry with the annular groove 3 when the control element 1approaches its upper dead center. As a result, the conduit 12 will tbeconnected with the pump work chamber 5 through conduit 4, so that theliquid displaced by the control element 1 will be forced finto theaccu-mulator chamber 9 not only through conduit 10, but also partiallythrough conduit 12. As soon as the control element 1 starts its suctionstroke, the accumulator piston 8, driven by its spring 22, starts itsreturn stroke during which it displaces liquid from the accumulatorchamber 9 into the pump work chamber '5 through conduit 12, throttlepassage 13, annular groove 3 `and conduit 4. As set forth hereinabove,the throttle 13 causes a braking of the return motion of the accumulatorpiston 8. This return motion is interrupted at the moment when theconduit 12 is closed as the groove 3 shifts out of registry therewith.

`For establishing and interrupting interconnection of the accumulatorchamber 9 with the cylinder 15, there is disposed on the control element1 a second annular groove 14 which is of such a `dimension that theconduit 16 is in communication therewith -at all times during theoperation of control element 1. Further, between the cylinder 15 and thebore 1a there is provided a port 17 which is arranged in such a mannerwith respect to the annular circumferential groove 14 that it willregister therewith only after the conduit 12 is closed by the uppersection of the control element 1. The port 17 remains open in the timeperiod in which the control element 1 reaches its low dead center andwill be closed again before the control element 1 begins to displaceliquid `from the pump work chamber 5 into the :accumulator chamber 9.

During the -time period in -which the accumulator chamber 9 is incommunication with the cylinder 15, ythe pressure in them is equal. If,now, both pistons 8 and 118 are 4in their position of rest at theirrespective abuttments 21 and 20, there is no liquid vliow across theconduit 16. Such a flow .may occur only if either the accumulator piston8 or the regulating piston 18 is away from its respective abutment.

The diameter of pistons 8 and 18 and the strength of springs 22 and 19are selected such that the hydraulic pressure which is necessary to liftthe accumulator piston 8 from its abutment 21 yis somewhat larger thanthe hydraulic pressure which is required to displace the regulatingpiston 18 from its abutment 20.

The spaces -for receiving Isprings 19 and 22 are connected to theambient atmosphere through openings 28 and 27, respectively.

The accumulator piston 8, shortly before it -opens the transfer port 23,opens a discharge port 24 which also leads to the liquid tank `7. Thecross-section `of the discharge port 24 is adjustable by means nowshown. The function of the discharge port 24 is to slow down the motionof the accumulator piston 8 during the terminal part of its upwardmovement and serves, during the first period of the return motion of theaccumulator piston 8, as an additional drain conduit. By these means thedegree of non-uniformity of the regulator device may he affected. Asimilar result may be reached by changing the elasticity of the spring22.

IPort 17, which connects the cylinder 15 with the bore 1a may beprovided with ya throttle passage 25 in order `to delay theestablishment of a -balanced pressure condition Ibetween theaccu-mulator chamber 9 and the cylinder 15.

From the bore 1a there extends an additional drain conduit 26 which, bymeans of the circuferential annular groove 3 of the control element 1,is opened shortly before the control element 1 reaches its upper deadcenter. In any other positions of the control element 1 the drainconduit 26 is closed. By opening the drain conduit 26, the return motionof the accumulator piston 8, in case of a significant drop in the r.p.m.of the engine, is accelerated and, consequently, the regulator piston 18is also allowed to rapidly move into its position of rest.

The abutments 20 and 21 may be adjusted by means not shown.

Operation of the embodiment FIG. l shows the control element 1 in itslower dead center -while the pistons 8 and 18 are in their position ofrest at their respective abutments 21 and 20. The pressure of theliquid, which now ows from the liquid supply tank 7 to the pump workchamber 5, is not suicient to` lift the accumulator piston 8 from itsabutment 21.

FIG. 2 shows the control element 1 at the end of its pressure stroke,that is, in its upper dead center after the liquid from the pump workchamber 5 has been displaced into the accumulator chamber 9. Theaccumulator piston 8 has been displaced into a position in which itopens at least the discharge port 24 but normally also the transfer port23.

During the rst part of the suction stroke of control element 1, that is,as long as the control element 1 maintains the conduit 12 closed, theaccumulator piston 8 moves in the direction of its abutment 21. As longas the r.p.m. of the cam (not shown) driving the control element 1 doesnot exceed a predetermined value, the accumulator piston 8 attains itsposition of rest against abutment 21 before an interconnection isestablished between the accumulator chamber 9 and the cylinder 15 byopening the port 17 by control element 1 towards the end of its suctionstroke. Stated in dilerent terms, the liquid displaced from theaccumulator chamber 9 by the returning accumulator piston 8 cannot,under the aforestated r.p.m. conditions expand into cylinder 15 and haveeffect on regulating piston 18 because the annular groove 14 of controlelement 1 registers with port 17 only after the accumulator piston 8 hascome to a rest against abutment 21. The regulating piston 18 remains,therefore, in its position of rest against its abutment 20 at whichposition the fuel injection pump delivers a maximum amount of fuel. If,now, the r.p.m. of the driving means associated with the control element1 increases -beyond a predetermined value as a response for acorresponding increase in the r.p.m. of the engine,

the accumulator piston 8, dependent upon the cross-section of thethrottle passage 13 which brakes its motion, does not return intoengagement with its abutment 21 due to the earlier closing of conduit 12by means of the control element 1 (FIG. 3).

At the moment, when the control element 1, towards the end of itssuction stroke, opens by means of the circumferential annular groove 14the channel 17, the liquid displaced by the downwardly movingaccumulator piston 8, may flow from the accumulator chamber 9 into thecylinder 15. As a result, the regulating piston 18, as depicted in FIG.4, is displaced towards the left. Due to this displacement, the fuelquantity supplied by the fuel injection pump is decreased by, c g.linkage means, not shown, connected to piston 18 and a quantity controlmember of the fuel injection pump.

The more the r.p.m. of the driving means for control element 1 increasesabove the aforenoted predetermined value, the higher is the position ofthe accumulator piston 8 at the moment the conduit 12 is closed by thecontrol element 1 and the more will the regulating piston 18 bedisplaced leftward during the end portion of each suction stroke ofcontrol element 1 and thus the more -Will the fuel quantities to beinjected decrease. The uppermost position that the accumulator piston 8may assume is determined by the location of the transfer port 23. Inthis position the spring 22 is compressed to a maximum eX- tent, thatis, the pressure in the accumulator chamber 9 has reached its highestvalue. This highest pressure is just suflicient to displace theregulating piston 18 into a position in which the fuel injection pumpdelivers a minimum amount of fuel.

As soon as the return motion of the accumulator piston 8 is stabilized,that is, its return strokes are of constant lengths and the regulatingpiston 18 has assumed a corresponding position, there is an equalpressure in the accumulator chamber 9 and in the cylinder 15.Consequently, when now the port 17 is opened at the end of each suctionstroke of control element 1, no liquid ows from the accumulator chamber9 into the cylinder 15.

If now, the r.p.m. of the driving means for the control element 1 againdrops, then the location which the accumulator piston 8 reaches at themoment when the conduit 12 closes, shifts in the direction of theabutment 21. As a result, the conforming pressure in the accumulatorchamber 9 also decreases so that the regulating piston 18 is, during theopen position of port 17, displaced by spring 19 in the direction of itsabutment 20 which results in an increase in the fuel quantity deliveredby the fuel injection pump.

1f the driving speed for the control element 1 drops rapidly, the drainconduit 26 causes an accelerated discharged of the accumulator chamber 9and, consequently, the regulating piston 18 will move rapidly into itsposition of rest with the end result of an accelerated increase in thefuel quantity delivered by the fuel injection pump.

By an appropriate choice of the ratio of diameters of the accumulatorpiston 8 and of the regulating piston 18, the number of strokes may bedetermined which is necessary to move the regulating piston 18 from oneposition of equilibrium into another.

By changing the cross-section of the throttle passage 13, the aforenotedpredetermined r.p.m. beyond which the novel regulator becomes effective,may be changed. Thus, the invention provides a regulator which may beset to maintain a desired r.p.m. anywhere between an idling speed and amaximum revolution per minute.

Conduit 12 may lead directly into a chamber of lower pressure such asthe liquid supply tank 7. Here too, however, a control element shouldkeep the conduit 12 open during the first part of the suction stroke andshould shut ol the `same during the second part thereof.

Although only one embodiment of the invention has been depicted anddescribed, it will be apparent that this embodiment is illustrative innature and that a number of modifications in the apparatus andvariations in its end use may be effected without departing from thespirit or scope of the invention.

What is claimed is:

1. A hydraulic regulator adapted to be associated with fuel injectionpumps for varying the quantities of fuel delivered by said fuelinjection pumps to internal combustion engines, said regulator operatingas a function of the r.p.m. of said engine and comprising,

(A) a chamber containing liquid of relatively high pressure,

(B) a chamber containing liquid of relatively low pressure,

(C) an accumulator chamber adapted to be periodically hydraulicallyconnected to said chamber containing liquid of relatively high pressureand to said chamber containing liquid of relatively low pressure,

(D) an accumulator piston slidably disposed in said accumulator chamberand adapted to assume a position of rest, said accumulator pistondisplaceable from its position of rest by said liquid of relatively highpressure,

(E) means urging said accumulator piston against the force of saidliquid of relatively high pressure and exerting to said accumulatorpiston a force increasing as a function of the displacement of saidaccumulator piston caused by said liquid of relatively high pressure,

(F) regulating means adapted to be periodically hydraulically connectedto said accumulator chamber,

(G) a plurality of hydraulic conduits connecting said accumulatorchamber with said chamber containing liquid of relatively high pressurewith said chamber containing liquid of relatively low pressure, and withsaid regulating means,

(H) a throttle passage in at least said hydraulic conduit connectingsaid accumulator chamber with said chamber containing liquid ofrelatively low pressure, said throttle passage adapted to dampen themotion of said accumulator piston, and

(l) a control element for causing an opening and closing of saidhydraulic conduits in a coordinated manner, said control elementadapted, in sequence, to establish a first communication between saidaccumulator chamber and said chamber containing liquid of relativelyhigh pressure, to establish a second communication between saidaccumulator chamber and said regulating means after breaking off saidrst communication and to establish a third communication between saidaccumulator chamber and said chamber containing liquid of relatively lowpressure in a time period after breaking off said vfirst communicationand before establishing said second communication, said control elementadapted to maintain said third communication for a duration being thefunction of the r.p.m. of said engine.

2. A hydraulic regulator as dened in claim 1, wherein said controlelement linearly reciprocates to perform alternating pressure strokesand suction strokes and is driven with a frequency depending upon ther.p.m. of said engine.

3. A hydraulic regulator as defined in claim 2 including a housinghaving a bore, said control element is formed as a piston and isslidably received in said bore, during said pressure strokes said boreconstitutes said chamber containing liquid of relatively high pressureand during said suction strokes said bore constitutes said chambercontaining liquid of relatively low pressure.

4. A hydraulic regulator as dened in claim 1 including an abutmentdisposed in said accumulator chamber and constituting said position ofrest for said accumulator piston and adapted to be engaged thereby, saidregulating means includes (A) a cylinder,

(B) a regulating piston slidably disposed in said cylinder and adaptedto assume a position of rest, said regulating piston displaceable fromits position of rest by the pressure of liquid introduced into saidcylinder,

(C) spring means urging said regulating piston into its position ofrest, and

(D) an abutment constituting said last named position of rest andadapted to be engaged by said regulating piston, said spring means andsaid means urging said accumulator piston against the force of saidliquid of relatively high pressure are dimensioned such that thehydraulic pressure necessary to displace said accumulator piston fromits position of rest is at least as large as the hydraulic pressurenecessary to displace said regulating piston from its position of rest.

5. A hydraulic regulator as dened in claim 4, wherein at least one ofsaid abutments is adjustable.

6. A hydraulic regulator as defined in claim 1 including a transfer portleading from said accumulator chamber, said transfer port adapted to -beopened by said accumulator piston when displaced to a maximum extent bysaid liquid of relatively high pressure, said relatively high pressurewhich is present in said accumulator chamber when said accumulatorpiston is displaced to said maximum extent is at least as large as thepressure necessary to displace said regulating means to a maximumextent.

7. A hydraulic regulator as dened in claim 6 including a throttlepassage leading from said accumulator chamber, said last named throttlepassage is adapted to be opened by said accumulator piston before thelatter opens said transfer port.

S. A hydraulic regulator as delined in claim 1, Wherein said hydraulicconduit connecting said accumulator chamber with said regulating meansincludes a throttle passage.

9. A hydraulic regulator as defined in claim 3 including a drain conduitleading from said bore, said control element adapted to maintain saiddrain conduit open upon completion of a pressure stroke and untilstarting a subsequent suction stroke.

References Cited UNITED STATES PATENTS 2,821,926 2/ 1958 Miller et al.103-37 2,905,457 9/ 1959 Emerson 137-36 2,928,376 3/1960 Levetus 137-363,141,414 7/1964 Bessier 103-41 3,267,865 8/ 1966 Deininger 103-41 XFOREIGN PATENTS 717,944 1/ 1932 France.

716,865 1/ 1942 Germany. 1,000,633 1/ 1957 Germany.

WILLIAM L. FREEH, Primary Examiner.

U.S. C1. X.R. 103-37; 137-36

